Bug 8023541

Bug Description:

This is a race bug.
The expected exception is a NullpointerException.
More details about this bug are at JDK-8023541 JIRA page.

Interleaving Description:

sun.rmi.server.Activation$SystemRegistryImpl

t1  t2    SystemRegistryImpl(int port,
                                   RMIClientSocketFactory csf,
                                   RMIServerSocketFactory ssf,
                                   ActivationSystem systemStub)
                    throws RemoteException
                {
1                   super(port, csf, ssf);
3                   this.systemStub = systemStub;
                }
        
                
                public Remote lookup(String name)
                    throws RemoteException, NotBoundException
                {
                    if (name.equals(NAME)) {
    2                   return systemStub;
                    } else {
                        return super.lookup(name);
                    }
                }

a) thread 1 initiates a SystemRegistryImpl instance at 1.
b) context switched, thread 2 returns systemStub at 2. But systemStub is still not initiated yet, so it returns a null value which is not expected.
c) context switched, thread 1 initiates systemStub at 3.

How To Reprocuce:

There are two stages to reproduce this bug:

• Stage 1: Modify the byte code of buggy class. The buggy window at original source code is very narrow, so we modify the byte code of buggy class to insert a short sleep between 1 and 3 in the code above to extend the buggy window to make the bug easier to reproduce.
  Run asm.ActivationModifier class first to generate a modified class file at this projet's "classes" directory.
• Stage 2: Run Test8023541 class with -Xbootclasspath/p:classes option to load modified class to replace the one from jdk.

This bug is reproduced under JDK 1.7.0.
It started at JDK 1.7.0, and hae been fixed since JDK 1.9.0.
Execute the following scripts to run the test to reproduce the bug (assume the location of the jdk7 test project is jdk7_test_home).

Linux:
${jdk7_test_home}/scripts/8023541.sh [--javaloc path]
Windows:
%jdk7_test_home%\scripts\8023541.bat [--javaloc path]